1. Field of the Invention
The present invention relates to an image processing mechanism, and more particularly, to an image processing method for determining a motion vector of an interpolated block, and a related apparatus.
2. Description of the Prior Art
In a conventional image interpolation mechanism, a motion vector of an interpolated block in an interpolated picture is directly determined according to a calculated result of a block matching algorithm and thereby an image of the interpolated block is generated according to the motion vector. Please refer to FIG. 1. FIG. 1 is a diagram illustrating an operation of the conventional block matching algorithm. As shown in FIG. 1, image pictures F2, F3 are sequential pictures of input images, an image picture Finter is an interpolated picture generated from the conventional image interpolation mechanism and A′˜L′ are background images of image pictures F2, F3, where each dotted-line arrow indicates a moving direction of a background image and each solid-line arrow indicates a moving direction of a foreground object. Background images F′˜I′ of the image picture F2 are covered by the foreground object whereas in the next image picture F3, background images C′˜F′ are covered by the foreground object. Since the block matching algorithm is capable of finding background images A′, B′, J′, K′, L′ within sequential image pictures F2, F3, a target motion vector of a corresponding block can be determined correctly and background images A′ B′, J′, K′, L′ can be displayed in the image picture Finter (as illustrated in FIG. 1). In addition, the block matching algorithm is also capable of finding an image of the foreground object within sequential image pictures F2, F3, therefore a target motion vector of a corresponding block can be determined correctly and an image of the foreground object can be displayed in image picture Finter.
When determining target motion vectors of interpolated blocks within regions Rinter and Rinter′, background images within regions Rinter and Rinter′, should, ideally, be able to be displayed since the target motion vectors of regions Rinter and Rinter′ are background motion vectors. For example, background images C′ and D′ ideally should be displayed in region Rinter while background images H′ and I′ should be displayed in region Rinter′. In fact, since the block matching algorithm cannot find background images C′, D′ (covered by a foreground object) in image picture F3 and, likewise, cannot find images H′, I′ (covered by a foreground object) in image picture F2, the block matching algorithm fails to determine motion vectors as normal, leading to an image distortion in the interpolated regions Rinter and Rinter′. When applied to a frame rate conversion, the conventional image interpolation mechanism degrades quality of output images by a significant amount.